Research Articles
In
ORGANIC MATTER DILUTION PROGRAMS for Sand-Based Putting Greens in Virginia
Virginia Tech Researchers: Erik H. Ervin, Ph.D., Associate Professor, Turfgrass Physiology; Adam Nichols, Research Specialist; Derik Cataldi and Kehua Wang, Graduate Students, Dept. of Crop and Soils Environmental Sciences; with Brandon Horvath, Ph.D., Assistant Professor of Plant Pathology, University of Tennessee Sponsors: Virginia Turfgrass Foundation, Virginia Agricultural Council, United States Golf Association (Green Section) and Smith Turf & Irrigation (Chris Bassett) Table 1. Treatment details & thatch/mat organic matter % at end of year.
#
Treatment Details
Total % removal
Total Disrupted Days, 2009
Nov. 2009
Days to 99% cover
Total
Nov. 2008
Fall % removal Sept. 10
Thatch/Mat (%OM)
Days to 99% cover
Sept. 10
Table 2. Total estimated days of disrupted putting quality in 2009 as affected by percent surface removal by various core cultivation and verticutting treatments. Spring % removal March 31
Surface Area Removed (%)
the 1990s, USGA Green Section-sponsored research provided Georgia-specific data for cultivation and topdressing recommendations — commonly known as “organic matter dilution” programs — for sand-based greens. USGA agronomists summarized the details of this approach, recommending annual cultivation practices that remove 15% to 20% surface area and incorporate 40 ft3 to 50 ft3 sand/M, with the ultimate goal being to maintain surface rootzone organic matter (OM) at 4% or less. Aggressive organic matter dilution programs are intended to slow the loss of aeration porosity (which subsequently reduces infiltration rates), thereby allowing superintendents to more easily manage their putting greens and lessen the effects of summer bentgrass decline. The objective of this trial is to compare various cultivation approaches that remove from 10% to 27% surface area and determine treatment effects
1
Untreated
0%
0
0%
0
0%
0
2
0.25” id core, 2 passes, in spring & fall
5%
24
5%
34*
10%
58*
11.8%
24
11.8%
21
23.6%
45
2.5% 31 +11.8%
2.5%
7
16.8%
38
#
Treatment Details
March 31
1
Untreated
0
0
0
5.2 a
4.3 a
2
0.25" id core, 2 passes, in spring & fall
5
5
10
4.9 ab
3.4 c
3
Verticut (3 mm blade), in spring & fall
3
Verticut (3 mm blade), in spring & fall
11.8
11.8
23.6
5.0 ab 3.9 ab
4
0.25” id + verticut (3 mm blade) in spring; 0.25” id core, in fall
4
0.25" id + verticut (3 mm blade), in spring; 0.25" id core, in fall
2.5 +11.8
2.5
16.8
5.2 a
3.7 bc
5
0.5” id core, in spring; 0.25” id core, 2 passes, in fall
9.8%
35
5%
33*
14.8%
88*
6
0.5” id core, in spring & fall
9.8%
36
9.8%
38
19.6%
74
5
0.5" id core, in spring; 0.25" id core, 2 passes, in fall
11.8
5
14.8
4.8 b
3.3 cd
7
0.5" id core, in spring; verticut (3 mm blade) + 0.25” id core, 2 passes, in fall
9.8%
35
6
0.5" id core, in spring & fall
9.8
9.8
19.6
4.8 b
3.0 d
7
0.5" id core, in spring; verticut (3 mm blade) + 0.25" id core, 2 passes, in fall
9.8
5+11.8
26.6
5.1 ab 3.3 cd
LSD 0.05
0.38
0.42
5% 52** 26.6% +11.8%
87**
* Two passes with the 0.25" inside diameter (id) tines on Sept. 10 resulted in undue tearing, hole overlap and furrowing on the putting surface that served to delay recovery in treatments #2 and #5 in September; this type of tearing did not happen with treatment #2 in the spring, so recovery was faster. ** Treatment #7 did not all occur on Sept. 10, as verticutting after 0.25" id doublepass coring caused undue sod lifting/damage. Verticutting was delayed until 26 days after coring, unduly lengthening recovery time to 52 days for this treatment.
10 | VIRGINIA TURFGRASS JOURNAL May/June 2010 www.vaturf.org